1. Field of Invention
The invention relates to a method for guiding a wireless communication device into a communicable range where the wireless communication device can achieve data communication with a communication target, and a wireless communication device that creates information used to place the wireless communication device back within the communicable range when the wireless communication device moves to a position out of the communicable range, using the above-described method.
2. Description of Related Art
Recently, Bluetooth® wireless technology is becoming widely used as a wireless communication system for enabling short-range wireless data communication between various devices. For example, wireless data communication is implemented between stationary electronic devices, such as desktop personal computers, printers and scanners, between portable electronic devices, such as cellular phones, PDAs (personal digital assistants) and notebook computers, or between the above-described stationary electronic devices and the above-described portable electronic devices.
The Bluetooth® wireless technology can carry out communication within a relatively short range (approximately between 10 to 100 meters in one-to-one communication) at low power consumption and a middle speed (approximately 1 Mbps). Further, the Bluetooth® wireless technology achieves downsizing of a communication module and excellent connectability between devices, especially between devices of different types.
Accordingly, the Bluetooth® wireless technology has been applied to various devices, mainly mobile terminals, such as cellular phones and PDAs, and is becoming increasingly common as one of the future mainstream wireless data communication systems. Because the Bluetooth® wireless technology achieves data communication at low power consumption and a downsized communication module, the communicable range in a one-to-one communication is as short as approximately 10 to 100 meters. Therefore, it often and easily happens that a Bluetooth® equipped terminal moves to a position out of the communicable range while carrying out the wireless communication with the other Bluetooth® equipped terminal.
There have been various methods for placing a wireless communication terminal back within a communicable range of a communication target when the wireless communication terminal moves to a position out of the communicable range of a communication target, in wireless communication technology other than the Bluetooth®. Those methods have been put into practical use. For example, there has been known a method such that, in wireless communication between a base station and a terminal, a distance between the terminal and the base station and a direction toward the base station from the terminal are displayed on a display of the terminal by detecting an electric field strength of radio waves from the base station.
However, it is difficult to implement the conventional guiding system using the electric field strength in the Bluetooth® wireless communication system. Under the present circumstances, manufacturers, who manufacture Bluetooth® wireless communication devices, purchase RF modules, baseband modules, firmware ROMs (which are recently integrated into a one-chip), and protocol stack software for controlling the modules, and create various applications by using the protocol stack API (application program interface) to control Bluetooth® modules.
The protocol stack is standardized in its detail. The protocol stack offers a means for controlling a power of radio waves of a device to control a lower module by an application or to obtain data from the lower module. However, the protocol stack does not include a means for controlling other controls and obtaining other data. Accordingly, information as to the electric field strength cannot be obtained by controlling the Bluetooth® module via an application layer. Accordingly, the conventional guiding method using the electric field strength cannot be applied to the Bluetooth® wireless system.